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Discussion Starter · #1 ·
I’m in the process of re-powering a JD 60 tractor with a 10hp Briggs from an Allis 810gt. Wiring has been simple up to the point of not recognizing the wiring coming from the alternator. I would like to snip off the connectors and wire a new setup to complete the circuit. Can this be done without replacing the current alternator? Included a photo of what I’m dealing with. Not sure if a regulator is needed for this engine as well. Only charging the battery, no auxiliaries.
 

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From what i've seen on small engines in general, they usually just have magnets on flywheel and a stator winding on engine block, which is going to put out AC voltage. It would then have to go through a 'rectifier' (diodes) to convert it to DC to feed to battery. If it does any fancy stuff like dumping excess voltage to avoid overcharging battery you might then call it a regulator. But either way the two wires coming out from under the flywheel cannot be hooked straight to battery without a rectifier/regulator.

If i'm wrong you could prove it by spinning engine while measuring those two terminals with a meter on AC voltage. If it makes no AC voltage and you switch your meter to DC volts and it makes DC volts, then maybe yes you could hook direct to battery. But i doubt it.
 

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Most single cylinder Briggs do not run a regulator / rectifier. They run a low amp single charging wire to the key switch Acc terminal. The second wire from the stator is usually a high amp circuit for running the lights or PTO clutch.

Best way to check would be to down load a wiring diagram for the Allis or check each wire from the stator to a ground and see if there is DC voltage.
 

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Discussion Starter · #4 ·
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This diagram shows a few different ways of wiring up a alternator. Would it be fine if I snipped off the old 856 wiring and change it over to the newer 877/878 wiring without putting a new alternator in? Parts are unavailable for the older setup. Part 501 is the regulator.
 

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The stator winding will not care what style of connectors are on the ends of its wires. The main thing you don't want to screw up in the process is the polarity of the connection to the rectifier. Diodes are 'directional' which means if you change up your connections and somehow end up hooking it up backwards, it's not going to work.

Also, if you mean 877 fine, if you mean 877a there's another caveat. 877a shows a single wire coming from the stator winding, where your 856 style has two. The 877a does HAVE two but you can't see one of them coming out because it's just going to ground to the engine housing through the mounting bolt of the stator winding. If you wanted to do 877a you'd have to ground your extra wire. But if you're switching from 2-wire 856 to 2-wire 877 then you won't be worried about that.

Most single cylinder Briggs do not run a regulator / rectifier. They run a low amp single charging wire to the key switch Acc terminal. The second wire from the stator is usually a high amp circuit for running the lights or PTO clutch.
Well i could see it not being a standalone component with its own name but it has to have rectification somewhere, which could mean diodes built into the electrical system somewhere else. The main reason a rectifier would tend to be on the engine itself is because diodes build up a fair amount of heat and the airflow around the engine would tend to limit its max temp. But unless the thing has a brushed permanent magnet DC generator, it HAS a rectifying device somewhere if it is charging a battery.

It is possible to leave it unrectified if you're not hooking it to a battery. If all you are doing is running lights, you can hook them straight to it because incandescent light bulbs work on both AC and DC anyway. So the same engine may be equipped with a rectifier when used in an electric-start application that recharges a starter battery, and not have a rectifier in an application where it's a pull start and the only electrical is lights and the on/off switch.

This is not engine-specific talk.. but sometimes that's best because the one thing that applies equally to everything.. is the laws of electricity and physics. :)
 

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Discussion Starter · #9 ·
@FrankIII I believe you are right, that is what I discovered while looking for parts.
Thanks @Vigo and others for the explanations. It is helpful. I’m going to go ahead and order some new parts and test the system once installed to confirm it’s working properly. Like I said, the electrical system is only utilized for engine and battery. No headlights or other electrical components on tractor.
 

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I have had my rounds with a few B&S charging coils over the last year on engine transplants, where I had to swap different stators for more charging capacity.
There are at least 4 different charging systems among them, one ac only, one ac/dc combo and a couple of higher amp ac ones that require a regulator to convert to DC power, just different amp ratings.
The stators do swap/interchange between families of Briggs engines over many years of production.
 

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The above are correct the small plugin with the black wire is for your lights. I would leave this disconnected and hook your lights to your battery. Otherwise your lights will be dim at idle and brighten when revved up. The bottom wire is for DC for charging. It needs to run through a diode before it can run to a switch so that the electricity can only flow one way. Other wise it will short circuit. Hope this helps. I have a simplicity 7014 with this same setup.
 

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Discussion Starter · #13 ·
The above are correct the small plugin with the black wire is for your lights. I would leave this disconnected and hook your lights to your battery. Otherwise your lights will be dim at idle and brighten when revved up. The bottom wire is for DC for charging. It needs to run through a diode before it can run to a switch so that the electricity can only flow one way. Other wise it will short circuit. Hope this helps. I have a simplicity 7014 with this same setup.
Does your engine use a voltage regulator? Or just a diode in the wiring coming from the alternator to the battery? Not planning on wiring lights on this tractor.
 

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Discussion Starter · #17 ·
It has no regulator it goes straight from the red wire through the diode and then to the key switch and then the battery. Voltage regulator was on starter generator models I think. Yours does not use a voltage regulator.
Another question: I could then get away with replacing the wiring with (877a) and (878a)?
 

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There are at least 4 different charging systems among them, one ac only, one ac/dc combo and a couple of higher amp ac ones that require a regulator to convert to DC power, just different amp ratings.
Wow, good info. I had wondered why the bother to separate the two ends of a stator winding (which is really just one long wire wrapped in a bunch of circles) into two totally different styles of connectors.. Having an ac side and a dc side makes that make more sense! Is item 486 the diode, by chance?
 

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Wow, good info. I had wondered why the bother to separate the two ends of a stator winding (which is really just one long wire wrapped in a bunch of circles) into two totally different styles of connectors.. Having an ac side and a dc side makes that make more sense! Is item 486 the diode, by chance?
I wondered about that. I think it might be a fuse, but maybe it's the diode. Usually the diode is inclosed in heat-shrink tubing right before the connector. That's on the more common single plug version.
 
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